IO NEW YORK STATE MUSEUM 



i An exposure of normal Rochester shales, above which lie 



2 Sixty feet of hard, dark gray dolomites, full of small cavities bearing 

 druses of dolomite and calcite, but with few or no fossils ; only parts of this 

 series are exposed (Lockport limestone) ; 



3 Two feet of porous dolomite, the cavities being vermicular or having 

 the aspect of small tubes (Lockport limestone) ; 



4 Three feet of dark gray dolomite. This is the lower Guelph bed. It 

 contains a fairly profuse fauna, of which Trematonotus alpheus is 

 the leading element, but Monomorella noveboracum the more 

 exclusive species (Monomorella bed). Both are highly abundant and 

 occur in extraordinarily fine specimens. Of other species the stratum 

 contains : Poleumita crenulata, Coelidium macrospira, 

 Lophospira bispiralis, Cyrtoceras orodes, Poteri- 

 oceras sauridens, Protophragmoceras patronus, Tro- 

 choceras desplainense, T. costatum, etc.; 



5 Eight feet of gray dolomite with few fossils, and these characterizing 

 the Lockport fauna : Zaphrentisbilateralis, Enterolasma c a 1 i - 

 culus, Strop heodonta profunda, Orthothetes subplanus 

 and a few others. This mass is capped by a thin bed of shaly limestone 

 containing a profusion of small fossils, among which are: Cladopora 

 multipora, Halysites catenularius, Lichenalia concen- 

 tric a, Dalmanella elegantula, Orthothetes subplanus, 

 Leptaena rhomboidalis, Camarotoechia neglect a, Rhyn- 

 chotreta cuneata americana, W h i t f i e 1 del la nitida 

 oblata, Spirifer crispus (typical Rochester shale form), Cor- 

 nulites arcuatus, Dalmanites sp., Calymmene cf. niaga- 

 rensis, Proetus sp. This association is characteristic of the Rochester 

 shale and lower Lockport limestone. Over this bed lies a thin layer of 

 chert nodules without fossils. 



6 Twenty-four feet of similar dark gray dolomite with fossils extremely 

 rare and of the same character as those below (Lockport limestone). 



7 Eight to io feet of gray dolomite, bearing white chert nodules most 



